1. Field of the Invention
The present invention relates to a stator assembly structure of a direct current brushless motor, and more particularly to a stator assembly structure of a direct current brushless motor which may decrease reluctance, and increase magnetic flux conducting effect, thereby further increase the rotational torque.
2. Description of the Related Prior Art
A conventional stator assembly in accordance with the prior art shown in FIGS. 1 and 2 comprises a shaft tube 901 fitted with an upper pole plate 902, a coil seat 903, and a lower pole plate 904. The coils of the coil seat 903 are energized to produce a magnetic field, thereby forming a magnetic force passage through the shaft tube 901, the upper pole plate 902, and the lower pole plate 904, while the end edges of the upper pole plate 902 and the lower pole plate 904 are induced with the annular permanent magnet of the rotor, so that the rotor can be driven to rotate. In such a conventional stator assembly, the thickness of the end edges of the upper pole plate 902 and the lower pole plate 904 forms an inducing face to induce with the annular permanent magnet of the rotor. Thus, the inducing face is small, so that the rotational torque is not enough, and the rotational speed is unstable.
Another conventional stator assembly in accordance with the prior art shown in FIGS. 3 and 4 comprises a shaft tube 911 fitted with an upper pole plate 912, a coil seat 913, and a lower pole plate 914. The upper pole plate 912 and the lower pole plate 914 each have bent side walls 915, 916 extending toward the coil seat 913. Such a conventional stator assembly has the side walls 915, 916, so that the side walls 915, 916 of the upper pole plate 912 and the lower pole plate 914 will form a larger inducing face to induce with the annular permanent magnet of the rotor. The upper and lower pole plates are each formed by bending a silicon steel plate with an equal thickness. Thus, the side walls 915, 916 increase the inducing face, but the thickness of the cross-section of the magnetic conducting passage of the upper and lower pole plates is not increased. Therefore, the rotational torque is not enough, and the rotational speed is unstable, thereby incurring a floating problem.
The primary objective of the present invention is to provide a stator assembly structure of a direct current brushless motor which has a better magnetic conducting effect, thereby increasing the rotational torque of the motor.
In accordance with the present invention, there is provided a stator assembly structure of a direct current brushless motor includes a coil seat wound with coils and provided with a fitting hole through which the magnetic conducting tube passes. An upper pole plate is mounted above the coil seat, and a lower pole plate is mounted under the coil seat. Each of the upper pole plate and the lower pole plate is provided with pole ends. At least one upper magnetic conducting plate and lower magnetic conducting plate are respectively bonded on the upper pole plate and the lower pole plate. Each of the upper pole plate, the lower pole plate, the upper magnetic conducting plate, and the lower magnetic conducting plate has a positioning hole through which the magnetic conducting tube passes. Side walls extending toward a vertical direction are at least formed on the pole ends of the upper pole plate, the lower pole plate, or one upper magnetic conducting plate, or one lower magnetic conducting plate.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.